Pub Date : 2023-08-10DOI: 10.1177/13506501231194668
Shoufan Cao, Zhang Xu, Yi Liang, S. Mischler
The tribocorrosion property of tungsten plays a great role in the chemical mechanical polishing of tungsten plugs used in integrated circuits. This study applied a lubricated tribocorrosion model to tungsten, verified and calibrated the model using results from laboratory tribocorrosion experiments, and predicted the effect of the key parameters on the mechanical and chemical wear behavior of tungsten. The results showed that the model could be successfully applied to the tribocorrosion of tungsten considering that the prevailing wear mechanism and the electrochemical corrosion property of tungsten fulfills the model's basic concepts. The model was able to predict the influence of the material, mechanical, electrochemical and rheological parameters on the mechanical wear and chemical wear behavior of tungsten. The model could clearly distinguish the contribution of the mechanical wear and chemical wear to the total wear degradation of tungsten, which provides useful instructions on how to control the related parameters in order to obtain tailored removal rate and surface quality in tungsten's chemical mechanical polishing process.
{"title":"Assessing the wear degradation of tungsten in acidic solutions using a lubricated tribocorrosion model","authors":"Shoufan Cao, Zhang Xu, Yi Liang, S. Mischler","doi":"10.1177/13506501231194668","DOIUrl":"https://doi.org/10.1177/13506501231194668","url":null,"abstract":"The tribocorrosion property of tungsten plays a great role in the chemical mechanical polishing of tungsten plugs used in integrated circuits. This study applied a lubricated tribocorrosion model to tungsten, verified and calibrated the model using results from laboratory tribocorrosion experiments, and predicted the effect of the key parameters on the mechanical and chemical wear behavior of tungsten. The results showed that the model could be successfully applied to the tribocorrosion of tungsten considering that the prevailing wear mechanism and the electrochemical corrosion property of tungsten fulfills the model's basic concepts. The model was able to predict the influence of the material, mechanical, electrochemical and rheological parameters on the mechanical wear and chemical wear behavior of tungsten. The model could clearly distinguish the contribution of the mechanical wear and chemical wear to the total wear degradation of tungsten, which provides useful instructions on how to control the related parameters in order to obtain tailored removal rate and surface quality in tungsten's chemical mechanical polishing process.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"74 1","pages":"1972 - 1982"},"PeriodicalIF":2.0,"publicationDate":"2023-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80471130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-07DOI: 10.1177/13506501231193068
Xu Luo, Cheng Cai, Hong S. Yang, G. Mei, Chang Gao, Weiping Liu, Dongsheng Yang
The present study simulated the actual contact conditions between the catenary and pantograph of a metro line using high-speed ring block current that carried friction and wear testers, from which the uneven wear of the pantograph carbon strip under different working conditions was studied. The results show that the arc power, friction coefficient, and wear amount will change correspondingly with increasing current and normal load. Additionally, all carbon strips showed non-uniform wear after the test, and the edge erosion and wear depth of the carbon strip perpendicular to the moving direction were higher than those in the middle part. The ablation of the back end of the carbon strip running with the catenary was higher than that of the front end.
{"title":"Experimental research on the non-uniform wear of the carbon strip of the metro pantograph","authors":"Xu Luo, Cheng Cai, Hong S. Yang, G. Mei, Chang Gao, Weiping Liu, Dongsheng Yang","doi":"10.1177/13506501231193068","DOIUrl":"https://doi.org/10.1177/13506501231193068","url":null,"abstract":"The present study simulated the actual contact conditions between the catenary and pantograph of a metro line using high-speed ring block current that carried friction and wear testers, from which the uneven wear of the pantograph carbon strip under different working conditions was studied. The results show that the arc power, friction coefficient, and wear amount will change correspondingly with increasing current and normal load. Additionally, all carbon strips showed non-uniform wear after the test, and the edge erosion and wear depth of the carbon strip perpendicular to the moving direction were higher than those in the middle part. The ablation of the back end of the carbon strip running with the catenary was higher than that of the front end.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"12 1","pages":"1943 - 1952"},"PeriodicalIF":2.0,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81203672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.1177/13506501231191852
Hao Jie, Xiaowei Yin, Shuang Zhu, Jungang Ren, Xiaokun Liu
Using a megawatt wind turbine disc brake as a case study, this work analyzes the effects and action mechanism of dynamic wear on the braking interface of the braking pad on tribological behaviors as contact state, temperature field, and pressure distribution. The Archard wear model was incorporated into the solution of the tribological problem of the braking interface in ABAQUS using the arbitrary Lagrangian–Eulerian (ALE) technique through the UMESHMOTION subroutine. The wear interface meshes were changed without modifying other finite element analysis variables. Moreover, wear testing on the inertia braking tester validated the coupled heat-stress-wear model of the brake pad. The differences in the tribological behaviors of the braking interface with and without the dynamic wear of the braking pad were analyzed based on the simulation results of friction and wear in a braking cycle. The study revealed that the tribological behaviors of the braking interface were significantly affected by the dynamic wear of the braking pad. Specifically, the wear evolution changed the contact state, the area of stress concentration, and the temperature field distribution during the braking process. Hence, the wear properties of the brake pad were modified as a result of these tribological behaviors.
{"title":"Analysis of the tribological behavior of the high-speed and heavy-load braking interface with dynamic wear of brake pads","authors":"Hao Jie, Xiaowei Yin, Shuang Zhu, Jungang Ren, Xiaokun Liu","doi":"10.1177/13506501231191852","DOIUrl":"https://doi.org/10.1177/13506501231191852","url":null,"abstract":"Using a megawatt wind turbine disc brake as a case study, this work analyzes the effects and action mechanism of dynamic wear on the braking interface of the braking pad on tribological behaviors as contact state, temperature field, and pressure distribution. The Archard wear model was incorporated into the solution of the tribological problem of the braking interface in ABAQUS using the arbitrary Lagrangian–Eulerian (ALE) technique through the UMESHMOTION subroutine. The wear interface meshes were changed without modifying other finite element analysis variables. Moreover, wear testing on the inertia braking tester validated the coupled heat-stress-wear model of the brake pad. The differences in the tribological behaviors of the braking interface with and without the dynamic wear of the braking pad were analyzed based on the simulation results of friction and wear in a braking cycle. The study revealed that the tribological behaviors of the braking interface were significantly affected by the dynamic wear of the braking pad. Specifically, the wear evolution changed the contact state, the area of stress concentration, and the temperature field distribution during the braking process. Hence, the wear properties of the brake pad were modified as a result of these tribological behaviors.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"20 1","pages":"1930 - 1942"},"PeriodicalIF":2.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83558373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-30DOI: 10.1177/13506501231190679
Chuang Wu, Yinbo Wang, F. Chen, X. Long
To the water lubricated bearing, its mixed-lubricated friction model is generally established based on the traditional statistical model, whose accuracy is not high due to the inaccurate characterization of surface topography. Therefore, this paper employs the fractal theory that has scale-independent characteristics and high precision to characterize the surface topography of the bearing and journal, and then establishes the fractal contact model of asperity, combining the average Reynolds equation of the film, proposes a mixed-lubricated friction model based on fractal theory. The scanning experiments of surface topography are carried out to obtain the fractal parameters and measurements of the friction coefficient are performed to verify the effectiveness of the proposed mixed-lubricated model. Subsequently, the proposed mixed-lubricated friction model is employed to analyze the effects of the number of groove, the position of groove and the fractal parameters on the lubrication and friction characteristics of the water lubricated bearing. Results indicate when the grooves are in the non-main load-carrying regions, the friction characteristics of the bearing slightly changes, and the lower surface roughness is beneficial to improve the lubrication and friction properties of the bearing.
{"title":"A mixed-lubricated friction model of water lubricated bearing based on fractal theory","authors":"Chuang Wu, Yinbo Wang, F. Chen, X. Long","doi":"10.1177/13506501231190679","DOIUrl":"https://doi.org/10.1177/13506501231190679","url":null,"abstract":"To the water lubricated bearing, its mixed-lubricated friction model is generally established based on the traditional statistical model, whose accuracy is not high due to the inaccurate characterization of surface topography. Therefore, this paper employs the fractal theory that has scale-independent characteristics and high precision to characterize the surface topography of the bearing and journal, and then establishes the fractal contact model of asperity, combining the average Reynolds equation of the film, proposes a mixed-lubricated friction model based on fractal theory. The scanning experiments of surface topography are carried out to obtain the fractal parameters and measurements of the friction coefficient are performed to verify the effectiveness of the proposed mixed-lubricated model. Subsequently, the proposed mixed-lubricated friction model is employed to analyze the effects of the number of groove, the position of groove and the fractal parameters on the lubrication and friction characteristics of the water lubricated bearing. Results indicate when the grooves are in the non-main load-carrying regions, the friction characteristics of the bearing slightly changes, and the lower surface roughness is beneficial to improve the lubrication and friction properties of the bearing.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"1 1","pages":"1913 - 1929"},"PeriodicalIF":2.0,"publicationDate":"2023-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88411408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-28DOI: 10.1177/13506501231190695
Arif Izzuddin Muhammad, Nurul Farhana Mohd Yusof, Z. M. Ripin
Mineral oil-based lubricants have been widely used for their beneficial properties. However, their environmental impact and toxicity have raised concerns, resulting in a search for sustainable and environmentally friendly alternatives. This study investigates the tribological behavior of palm olein-based grease with copper nanoparticles additive concentrations of 0.25 and 0.50 wt%. The friction and wear tests were conducted using a four-ball tribometer to evaluate the performance of the formulated grease and compare it with commercial mineral grease. The results showed that the palm olein-based grease with a 0.25 wt% copper nanoparticle additive concentration had excellent lubricant performance, with low friction and wear prevention characteristics. This concentration of Cu nanoparticles led to a 35.05% reduction in average friction coefficient (COF), a 32.56% reduction in wear scar diameter (WSD), and a 48.02% reduction in wear volume compared to pure palm olein-based grease.
{"title":"The tribological performance analysis of palm olein-based grease lubricants containing copper nanoparticle additive","authors":"Arif Izzuddin Muhammad, Nurul Farhana Mohd Yusof, Z. M. Ripin","doi":"10.1177/13506501231190695","DOIUrl":"https://doi.org/10.1177/13506501231190695","url":null,"abstract":"Mineral oil-based lubricants have been widely used for their beneficial properties. However, their environmental impact and toxicity have raised concerns, resulting in a search for sustainable and environmentally friendly alternatives. This study investigates the tribological behavior of palm olein-based grease with copper nanoparticles additive concentrations of 0.25 and 0.50 wt%. The friction and wear tests were conducted using a four-ball tribometer to evaluate the performance of the formulated grease and compare it with commercial mineral grease. The results showed that the palm olein-based grease with a 0.25 wt% copper nanoparticle additive concentration had excellent lubricant performance, with low friction and wear prevention characteristics. This concentration of Cu nanoparticles led to a 35.05% reduction in average friction coefficient (COF), a 32.56% reduction in wear scar diameter (WSD), and a 48.02% reduction in wear volume compared to pure palm olein-based grease.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"26 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72793407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-27DOI: 10.1177/13506501231189317
Thachnatharen Nagarajan, Mohammad Khalid, H. Zaharin, N. Sridewi
The frictional stress between opposing contact surfaces will damage the mechanical parts of a machine. An appropriate lubricant can significantly reduce this. Blending nanoadditives with base oil is claimed to be an effective technique to increase the anti-friction qualities of lubricants using nanotechnology. Advanced microwave synthesized molybdenum disulfide (MoS2) anti-friction nanoadditive was employed in various lubricating oils namely fully synthetic, semi-synthetic, mineral, and hydraulic oil to formulate the nanolubricant. X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX), and a physical stability observation test were used to study the nanoadditives (MoS2) physicochemical characteristics. The tribological analysis of the MoS2 nanolubricant was measured using the four-ball tribotester. The coefficient of friction (COF) and average wear scar diameter (WSD) of the anti-friction additives were analyzed. The experimental results revealed improvements in COF and WSD in the range of 7.47–15.81% and 6.57–16.07% after the addition of MoS2 nanoparticles in the various lubricating oils. This study discovered that engine oil with advanced microwave-synthesized MoS2 nanoparticles has a significantly lower COF and WSD than engine oil that is not added with the anti-friction additives.
{"title":"An investigation on tribological properties of advanced microwave synthesized molybdenum disulfide as anti-friction additives in commercially available lubricating oils","authors":"Thachnatharen Nagarajan, Mohammad Khalid, H. Zaharin, N. Sridewi","doi":"10.1177/13506501231189317","DOIUrl":"https://doi.org/10.1177/13506501231189317","url":null,"abstract":"The frictional stress between opposing contact surfaces will damage the mechanical parts of a machine. An appropriate lubricant can significantly reduce this. Blending nanoadditives with base oil is claimed to be an effective technique to increase the anti-friction qualities of lubricants using nanotechnology. Advanced microwave synthesized molybdenum disulfide (MoS2) anti-friction nanoadditive was employed in various lubricating oils namely fully synthetic, semi-synthetic, mineral, and hydraulic oil to formulate the nanolubricant. X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX), and a physical stability observation test were used to study the nanoadditives (MoS2) physicochemical characteristics. The tribological analysis of the MoS2 nanolubricant was measured using the four-ball tribotester. The coefficient of friction (COF) and average wear scar diameter (WSD) of the anti-friction additives were analyzed. The experimental results revealed improvements in COF and WSD in the range of 7.47–15.81% and 6.57–16.07% after the addition of MoS2 nanoparticles in the various lubricating oils. This study discovered that engine oil with advanced microwave-synthesized MoS2 nanoparticles has a significantly lower COF and WSD than engine oil that is not added with the anti-friction additives.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"118 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87636168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-19DOI: 10.1177/13506501231186845
Xinli Zhong, Jingjun Jiang, G. Bin, Anhua Chen, Feng Yang
The internal thread texture causes changes in the dynamic characteristics of the oil film of the semi-floating ring bearing, which affects the amplitude of vibration and operating life of the turbocharger rotor system. Based on the fluid lubrication theory, the oil film governing equation of a semi-floating ring bearing with surface texture parameters is derived. The effects of the texture depth, position, and number of turns of the internal thread on the dynamic characteristics of the bearing oil film, such as the maximum pressure, load-carrying capacity and stiffness damping, are analyzed. Taking a type of turbocharger as an example, a hydrodynamic model is established to analyze the oil film lubrication in the semi-floating ring bearings, and the dynamic characteristic of the oil film is analyzed by computational fluid dynamics method. The results show that the maximum pressure, bearing capacity, and stiffness damping coefficient of oil film increase firstly and then decrease with the increase of texture depth and the number of thread turns in the range of journal rotation speed from 1000 to 20,0000 r/min. Compared with the non-texture bearings, the dynamic characteristics coefficients of the oil film such as bearing capacity and stiffness damping increase the most, when the depth of texture is 0.006 mm and the number of thread turns is 9. Secondly, the dynamic characteristic coefficient of oil film is improved when the texture is distributed in the middle than on both sides. The thread texture with appropriate parameters can suppress the rotor system vibration amplitude. The conclusion can provide a reference for the design of textual parameters of semi-floating ring bearings.
{"title":"Vibration characteristics of turbocharger rotor system considering internal thread texture parameters of semi-floating ring bearing","authors":"Xinli Zhong, Jingjun Jiang, G. Bin, Anhua Chen, Feng Yang","doi":"10.1177/13506501231186845","DOIUrl":"https://doi.org/10.1177/13506501231186845","url":null,"abstract":"The internal thread texture causes changes in the dynamic characteristics of the oil film of the semi-floating ring bearing, which affects the amplitude of vibration and operating life of the turbocharger rotor system. Based on the fluid lubrication theory, the oil film governing equation of a semi-floating ring bearing with surface texture parameters is derived. The effects of the texture depth, position, and number of turns of the internal thread on the dynamic characteristics of the bearing oil film, such as the maximum pressure, load-carrying capacity and stiffness damping, are analyzed. Taking a type of turbocharger as an example, a hydrodynamic model is established to analyze the oil film lubrication in the semi-floating ring bearings, and the dynamic characteristic of the oil film is analyzed by computational fluid dynamics method. The results show that the maximum pressure, bearing capacity, and stiffness damping coefficient of oil film increase firstly and then decrease with the increase of texture depth and the number of thread turns in the range of journal rotation speed from 1000 to 20,0000 r/min. Compared with the non-texture bearings, the dynamic characteristics coefficients of the oil film such as bearing capacity and stiffness damping increase the most, when the depth of texture is 0.006 mm and the number of thread turns is 9. Secondly, the dynamic characteristic coefficient of oil film is improved when the texture is distributed in the middle than on both sides. The thread texture with appropriate parameters can suppress the rotor system vibration amplitude. The conclusion can provide a reference for the design of textual parameters of semi-floating ring bearings.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"24 1","pages":"1796 - 1808"},"PeriodicalIF":2.0,"publicationDate":"2023-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81502842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-19DOI: 10.1177/13506501231188358
S. C. Cagan, B. B. Buldum
This study primarily focuses on green machining, which refers to the environmentally friendly machining of parts without compromising the environment and human health. Green machining, an innovative approach in the manufacturing industry, aims to reduce the environmental impact and promote sustainable practices throughout the machining process. Green machining involves the utilization of methods such as machining, dry machining, high-performance cutting, hybrid machining, and high-speed cutting, along with environmentally friendly lubrication practices. The objective of this research is to investigate the effects of machining Ti6Al4V alloys, a widely used lightweight metal in the aerospace industry known for its challenging machinability. The study specifically examines cutting force, surface roughness, and tool wear under various cutting parameters and tribological conditions. The use of a new lubrication/cooling method was investigated in order to minimize the effects of traditional cutting fluids used in the machining of difficult materials, which may cause environmental and human health. This way, sustainable green production compatible with the environment has been realized today, where global warming and carbon emissions are rapidly increasing. In addition, it was observed that the factor determining the cutting force was the depth of cut and the feed rate was the most significant factor affecting the surface roughness.
{"title":"A green machining study to investigate the effect of nano-cutting fluid environments on the machinability of Ti6Al4V titanium alloy","authors":"S. C. Cagan, B. B. Buldum","doi":"10.1177/13506501231188358","DOIUrl":"https://doi.org/10.1177/13506501231188358","url":null,"abstract":"This study primarily focuses on green machining, which refers to the environmentally friendly machining of parts without compromising the environment and human health. Green machining, an innovative approach in the manufacturing industry, aims to reduce the environmental impact and promote sustainable practices throughout the machining process. Green machining involves the utilization of methods such as machining, dry machining, high-performance cutting, hybrid machining, and high-speed cutting, along with environmentally friendly lubrication practices. The objective of this research is to investigate the effects of machining Ti6Al4V alloys, a widely used lightweight metal in the aerospace industry known for its challenging machinability. The study specifically examines cutting force, surface roughness, and tool wear under various cutting parameters and tribological conditions. The use of a new lubrication/cooling method was investigated in order to minimize the effects of traditional cutting fluids used in the machining of difficult materials, which may cause environmental and human health. This way, sustainable green production compatible with the environment has been realized today, where global warming and carbon emissions are rapidly increasing. In addition, it was observed that the factor determining the cutting force was the depth of cut and the feed rate was the most significant factor affecting the surface roughness.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"11 1","pages":"1841 - 1853"},"PeriodicalIF":2.0,"publicationDate":"2023-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75151481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-18DOI: 10.1177/13506501231188758
Deliang Hua, R. Li, Xiujiang Shi, Wen Sun, Fangpeng Shi, Xi-qun Lu
The working conditions of cam-tappet pairs in marine diesel engines are directly influenced by the engine output power, the operational speed, the temperature, as well as the components surface micro-morphology, etc., which cause the cam-tappet pairs work in the mixed lubrication state, thus the interfacial friction, pressure and temperature rise are vital to engine performance, efficiency, and durability. An interfacial friction–temperature prediction model for the cam-tappet pairs, considering the effects of transient working conditions and the real surface roughness, is developed in the present study, based on the theories of the transient mixed EHL and the heat transfer under the condition of a fast moving heat source. The numerical results of surface temperature rise are compared with those from the Blok formula, and a good agreement is found. The obtained results show that the presence of 3D roughness may lead to a decrease in the lubricant film thickness, and the surface temperature rise of tappet may exceed 700 K, which is close to the material scuffing temperature, causing the surface failure due to scuffing and wear. If increasing the cam speed and base circle radius within certain range, it may lead to the increment of film thickness and reduction of surface temperature rise, thus the lubrication effectiveness is increased. In addition, using cast aluminum bronze may significantly reduce the surface temperature rise and improve the interfacial characteristics.
{"title":"Predictions of friction and temperature at marine cam-tappet interface based on mixed lubrication analysis with real surface roughness","authors":"Deliang Hua, R. Li, Xiujiang Shi, Wen Sun, Fangpeng Shi, Xi-qun Lu","doi":"10.1177/13506501231188758","DOIUrl":"https://doi.org/10.1177/13506501231188758","url":null,"abstract":"The working conditions of cam-tappet pairs in marine diesel engines are directly influenced by the engine output power, the operational speed, the temperature, as well as the components surface micro-morphology, etc., which cause the cam-tappet pairs work in the mixed lubrication state, thus the interfacial friction, pressure and temperature rise are vital to engine performance, efficiency, and durability. An interfacial friction–temperature prediction model for the cam-tappet pairs, considering the effects of transient working conditions and the real surface roughness, is developed in the present study, based on the theories of the transient mixed EHL and the heat transfer under the condition of a fast moving heat source. The numerical results of surface temperature rise are compared with those from the Blok formula, and a good agreement is found. The obtained results show that the presence of 3D roughness may lead to a decrease in the lubricant film thickness, and the surface temperature rise of tappet may exceed 700 K, which is close to the material scuffing temperature, causing the surface failure due to scuffing and wear. If increasing the cam speed and base circle radius within certain range, it may lead to the increment of film thickness and reduction of surface temperature rise, thus the lubrication effectiveness is increased. In addition, using cast aluminum bronze may significantly reduce the surface temperature rise and improve the interfacial characteristics.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"386 1","pages":"1854 - 1867"},"PeriodicalIF":2.0,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86819691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-12DOI: 10.1177/13506501231187017
Seyed Abbas Asgari, Reyhaneh Gholami, Mohammad Reza Tavakoli Nejad, A. Allafchian, S. Akbarzadeh
In this paper, the effect of adding Reduced Graphene Oxide (RGO) nano-particles to engine base oil (Poly-Alpha-Olefin-PAO) on the thermo-physical properties of nano-fluid such as viscosity, thermal conductivity, and friction coefficient, are investigated numerically and experimentally. To keep the nano-fluid stable, before using ultrasonic waves, two types of polysorbate (tween 20 and tween 80) as surfactants were added to four concentrations of 0.01, 0.02, 0.0375, and 0.05 wt%, and the effects of nano-particles were studied to find the best combination in terms of viscosity, thermal conductivity, and friction coefficient, which made the nan-fluid quite stable during the tests procedure. The results showed with good accuracy that the final nano-fluid was Newtonian and its viscosity was very similar to the base oil. An increase of 7% was observed between 25 °C and 75 °C and for the concentration of 0.02 wt%. Thermal conductivity was raised in all states with an increase in concentration and the highest effect was 8% in the concentration of 0.05 wt%. The friction tests proved a desirable decrease of as much as 45% in friction coefficient compared to base oil and 28% compared to common anti-friction material used in industry for the optimum concentration which was 0.02 wt%. In addition, experimental data were compared to the models presented in the literature and the models that could describe the behavior of this nano-fluid in the best way were reported, and an empirical equation (for each surfactant) is developed to show the variation of COF with nano-particles weight fraction in the nano-fluid.
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